The treatment cascade

Diagrams of the ‘treatment cascade’ provide a useful way of
visualising problems with the implementation of ‘treatment as prevention’ in
specific contexts, and of identifying reasons why HIV treatment may not have as
great an impact as could be hoped.

In most parts of the world, large gaps exist between the
number of people who have HIV, those who know that they have HIV, those
attending medical services, and those receiving effective treatment. For
example, the treatment cascade for the United States shows that just 28%
of those living with HIV have a suppressed viral load. This means that
treatment may only have a limited impact on the American epidemic, except in
places where barriers to accessing medical care have been removed.

The equivalent diagram for the UK is more encouraging. Around 76,800
adults were living with diagnosed HIV in 2012, of whom 88% (67,600) were receiving
antiretroviral treatment. Between 71% (54,800) and 78% (59,900) of adults with
diagnosed HIV had an undetectable viral load (<50 copies/ml).

We also know that 97%
of people newly diagnosed with HIV were connected with specialist care
within three months, and 95% of people who attended during one year were
retained in care the following year. Few other countries have comparable
results.

Furthermore, there is equality in these results, with
similar figures in people of different ages, ethnicities, genders, exposure
groups and geographical regions. One exception is that younger people are less
likely to take treatment than older people.

As a result, only six in ten of those with HIV have an
undetectable viral load. It is clear that for treatment as prevention to
achieve its potential in the UK,
a priority is for interventions targeting the first step in the treatment
cascade – in other words, programmes which reduce the number of people with
undiagnosed HIV.

In African countries, the United States and elsewhere, health
systems are often so dysfunctional that there is considerable scope to improve
the numbers of people who attend medical care and receive HIV treatment. In
contrast, HIV care in the UK
is already of very high quality. Specifically, there are few bureaucratic or
financial barriers to accessing HIV clinics in the NHS, including by people of
uncertain immigration status. However, if NHS policies were changed, this could
have a negative impact on engagement with care.

Moreover, while overall levels of linkage to care, retention
and adherence to therapy are good, some individuals do drop out of care, attend
irregularly or have problems taking their medications as prescribed. High
quality, personalised support may be needed.

Finally, some individuals living with HIV may not be aware
of the preventive benefits of treatment and of BHIVA’s recommendation
that any patient wishing to take HIV treatment for that reason may do so. More
information for people with HIV and their partners could be provided.

Who is infectious?

In the UK, there are
far more individuals with undiagnosed HIV than individuals with diagnosed HIV
who are not taking antiretroviral therapy. One analysis estimated that,
in 2010, there were 14,000 HIV-positive MSM (men who have sex with men) with
a viral load above 1500 copies/ml. Within this group of ‘infectious’ men:

62% (8700
men) were undiagnosed

5% (700
men) were on treatment which was not yet fully effective

16%
(2300 men) were not on treatment and had a CD4 cell count above 500 cells/mm3

12%
(1600 men) were not on treatment and had a CD4 cell count between 350 and 500
cells/mm3

5%
(700 men) were not on treatment and had a CD4 cell count below 350 cells/mm3

Taken
together, these men amount to 35% of all HIV-positive MSM in the country. The researchers examined which strategies
would be most effective in reducing the size of this group. Getting all diagnosed men with a CD4 cell count
below 500 onto treatment would reduce the proportion to 29%, while halving the number of undiagnosed men
through increased HIV testing would reduce the proportion to 27%. It would be
more effective to combine both approaches – bringing the proportion down from
35 to 21%.

HIV treatment as prevention

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

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This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends
checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member
of your healthcare team for advice tailored to your situation.